Space current device



A g- 1932- R. G. BERTHOLD 1,871,443

SPACE CURRENT DEVICE Filed Sept. 26, 1925 INVENTOR Patented, Aug. 16, 1932 UNITED STATES PATENT OFFICE BUDOL'I' G. BEBTHOLD, OF BERLIN-SIEMENSSTADT, GERMANY, ASSIGNOB, 'I'O WESTING- HOUSE ELECTRIG G5 MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VAN IA Application filed September 26, 1925, Serial No. 58,848, and in Germany October 6, 1924.

My invention relates to space-currentdevices and it has particular relation to highvacuum tubes in which the current is carried principally by electrons.

High-vacuum electron tubes, which have the great advantage of being susceptible of a very close control of the current between the cathode and the anode, by controlling the space charge therebetween, are limited in their capacity because of the limited number of electrons that can be emitted from the incandescent cathodes heretofore utilized in such tubes.

The principal object of the present invention is to provide a space-current tube in which the current is carried principally by electrons and which is capable of operating with much larger currents than those heretofore used. According to my invention, the electrons utilized to carry the current between the cathode and the anode are supplied from a gaseous discharge, such as an arc or a glow discharge, in a difi'erent portion of the tube, wherein conduction takes place principally by means of ionized gaseous particles. The tubes are so constructed as to restrict the are or gaseous discharge to its own portion of the tube, thus obtaining a substantially pure electron discharge through the vacuum space to the main anode. The tube may be provided with control electrodes such as grids, and the electron current in the tube may be readily adjusted by controlling the potential of the grids or by any other known means for controlling the current in a substantially pure electron discharge.

Referring to the drawing, Fig. 1 is a sectional view of an electron tube embodying my invention, and

Figs. 2 and 3 are similar views of electron tubes embodying modifications of my invention.

Referring to Fig. 1, a cylindrically shaped envelope 1 of insulating material, such as glass, has a depending portion 2 containing a mercury cathode 3 with which contact is made by means of a terminal wire 4. The top of the cylindrical envelope is provided with an extension 5 in which is mounted a solid electrode 6 held upon a sealed-in terminal wire 7. The solid electrode 6 is arranged to act as an auxiliary anode for maintaining an arc discharge With the mercury electrode 3. A cylindrical main anode 8 is mounted within the envelope 1, surrounding the arc path 9 extending between mercury cathode 3 and the auxiliary anode 6.

The main anode 8 is separated from the mercury arc path 9 by a cylindrical separatorwall or partition 11, dividing the interior of the envelope 1 into a central longitudinal cathode chamber 12 extending between the mercury cathode and the auxiliary anode 6, and an anode chamber 13 surrounding the middle portion of the cathode chamber.

To operate the device, a mercury are discharge 9 is maintained between the mercury cathode 3 and the auxiliary anode 6' by means of an energy scource .14. The partition or separator 11 which surrounds the mercury arc discharge 9 is so constructed as to permit the passage of electrons from the are discharge towards the main anode 8, while preventing the passage of gas particles into the main anode chamber 13. The action just mentioned is obtained by providing the cylindrical periphery of the separator 11 with openings 15 which are inclined in such manner that the vapor stream from the mercury cathode 3 to the anode exercises a pumping or evacuating action upon the space of the main anode chamber, tending to maintain a high vacuum in the main anode chamber.

The electron flow from the arc discharge will not be seriously impaired by the suction action exercised by the mercury vapor, while the heavier molecular particles of the vapor and residual gases are sucked into the inner chamber by the upwardly streaming mercury vapor blast. An electron current of large capacity may thus be obtained by connecting a load 16 in series with an energy source 17 bgtween the anode 8 and the mercury catho e 3.

The electron current flowing between the arc dischar e 9 and the main anode 6 may be controlled l ny means of auxiliary electrodes placed in the space between the arc discharge and the anode. In the electron tube shown in Fig. 1, the partition 11 surrounding the in Fig. 2, the arc discharge is maintained as an electron-emitting electrode, in accor ance with my invention, it is possible to obtain much larger electron currents than by utilizing an incandescent solid electrode, At the same time, the current between the arc discharge and the main anode retains the.

character of a pure electron discharge, through the evacuating action of the vapor blast in conjunction with the perforations in the partition surrounding the arc discharge, the evacuatin action being similar to that of a va or di usion-pum v To 0 tain an increase evacuating action in the main anode chamber 13, the up er extension 5 of the envelope may be utilized as a condensation chamber for the mercury 47 vapor, thus increasing the velocity of the vapor blast. To this end, the upper extension 5 around the auxiliary anode 6 is surrounded by a jacket 21 through which a cooling li uid 22 is circulated. The container 1 may be rther evacuated by connecting a tubular extension 23, leading from the upper chamber 5, to a suitable vacuum pump, not shown in the drawing.

In a modification of my invention shown between an auxiliary solid anode 25 which is mounted on the bottom of a cylindrical envelope 26, and a mercury cathode 27, which is contained in a grooved portion 28 of a pearshaped extension 29 on the top of the envelope 26. The space of the arc discharge between the auxiliary anode 25 and the mercury cathode 27 is enclosed by a porous diffusion diaphragm 30 of cylindrical shape, the main anode 31 surrounding the difi'usion diaphragm.

I have found that a diflusion diaphragm, of the kind used in osmotic processes, very efi'ectively prevents gaseous molecules from passing into the anode chamber on account of the relatively great volume and large mass of the gas particles. On the other hand, the diaphragm presents very little resistance to the flow of electrons therethrough from the arc discharge toward the main anode 31. As a material for the diaphragm, I may use unglazed porcelain or a similar ceramic material. The diaphragm may also be made of other semi-conductors or non-conductors such as, rare earths, compounds of aluminum, magnesium and similar light metals, or other material having similar characteristics.

In order to increase the flow of electrons toward the anode, the diaphragm may be maintained at incandescence by suitably heating the same.

The stream of the mercury vapor along the walls of the diaphragm 30, produces an interior of the dividing said ,mounted in evacuating action similar to that obtained in the construction shown in Fig. 1. The

of an electrode 32 dis osed therebetween. I

In a modification o my inven ion shown in Fig. 3, a discharge tube having a depending bottom portion 41, similarto that of Fig.1, is provided with a pear-shaped upper extension 42, similar to that of the device shown in Fig.2, containing a mercury electrode 43 WhlCh is used in conjunction with a second mercury electrode 44 disposed in the bottom portion 41, to maintain an are discharge which supplies the electrons throu h a porouscdia hragm 45 similar to that 1n Fig. 2. The 'aphragm 45 is shown provided with a heating coil 46 for maintaining the same at a temperature at which it will increasethe electron flow toward the anode The several modifications shown and described hereinabove are only illustrative of the broad principles utilized in the construction of a space-current device wherein a pure electron discharge is maintained by means ing as a cathode, and it is desired t at the appended claims shall be broadly construed to cover all modifications falling within the spirit of my invention.

'I claim as my invention V 1. A space-current device having an envelope and comprising a diffusion diaphragm envelope into an anode chamber and a cathode chamber, an anode mounted in said anode chamber, two electrodes said cathode chamber, for maintaining a gaseous discharge in said cathode chamber, said diffusion diaphragm permitting a flow of electrons from said discharge to said anode, but obstructing the flow of gaseous ions therebetween.

2. A space-current device comprising a hermetically closed envelope, a diffusion diaphragm dividing said envelope into an anode .anode in said cathode chamber for main taining an arc-discharge, said separator having openings to cause a pumping action by the stream of mercury vapor from said cathode, a portion of said cathode chamber extending within said anode chamber and the of-an auxiliary gaseous or are dischar e servremaining portion extending outside said anode chamber.

4. A space-current device comprising-an evacuated envelope, a separator dividing said envelope into an anode chamber and a cathode chamber, an anode in said anode chamber, and a mercury cathode and an auxiliary anode in said cathode chamber for maintaining an arc-discharge, said separator having very small passages for preventing the passage of conducting vapor from said cathode chamber to said anode chamber but permitting a flow of electrons therebetween, a portion of said cathode chamber being surrounded by said anode chamber and the remaining portion extending outside said anode chamber.

In testimony whereof, I have hereunto subscribed my name this 5th day of Septemher 1925.

RUDOLF G. BERTHOLD. 

